Add a cleanup workflow for the system tests runner (#645)

Author: MakisH

.github/workflows/system-tests-cleanup.yml

@@ -0,0 +1,21 @@
+name: System tests cleanup
+
+on:
+  schedule:
+    - cron: "0 3 1 * *"
+  workflow_dispatch:
+
+jobs:
+ cleanup-system-tests-runner:
+    name: Cleanup system tests runner
+    runs-on: [self-hosted, linux, x64, precice-tests-vm]
+    steps:
+      - name: Report disk usage before cleanup
+        run: |
+          df -h | grep -E '(Filesystem|/var)'
+      - name: Run docker system prune
+        run: |
+          docker system prune --all --force
+      - name: Report disk usage after cleanup
+        run: |
+          df -h | grep -E '(Filesystem|/var)'

changelog-entries/645.md

@@ -0,0 +1 @@
+- Added a workflow to cleanup the system tests runner [#645](https://github.com/precice/tutorials/pull/645)